//
// Created by ASUS on 2024/10/19/星期六.
//
#include <bits/stdc++.h>
using namespace std;

int dx[4]={-1,0,0,1},dy[4]={0,-1,1,0};

void func(){
	vector<vector<int>> grid;
	int m=grid.size(),n=grid[0].size();

	queue<pair<int,int>> q;
	q.push(make_pair(0,0));
	grid[0][0]=0;
	while(!q.empty()){
		int x=q.front().first,y=q.front().second;
		q.pop();
		for(int i=0;i<4;i++){
			int nx=x+dx[i],ny=y+dy[i];
			if(nx>=0&&nx<m&&ny>=0&&ny<n&&grid[nx][ny]!=0){
				grid[nx][ny]=0;
				q.push(make_pair(nx,ny));
			}
		}
	}

}